54 THE ITCH-MITE OF MAN. 
THE ITCH-MITE OF MAN. 
(Sarcoptes scabtei De G. var. hominis). 
This mite (fig. 27 and 28) is very minute, whitish, 
and barely visible to the naked eye unless moving over a 
dark surface. Its body is rounded and soft, in the female 
with small roundish scales upon the middle of the back; in 
the male with but few isolated scales; the surface of the body 
has radiating lines or. ridges. The mites resemble in a 
general way a minute tortoise, are very sluggish during the 
day, but become quite active during the night in a warm bed, 
and can even leap to some distance. The head is distinctly 
separated from the rest of the body, and possesses four pairs. 

Fig. 27.—Itch-mite of Fig. 28.—Itch-mite of man, 
man, male. Greatly en- female. Greatly enlarged. Orig- 
larged. Original inal. 
of jaws which areneedle-like. The mite has eight legs, four in 
front and four behind; when young, or as a larva, it has 
but six legs. The sides of the bedy and legs bear long bristle- 
like hairs; there are six upon the thorax and fourteen upon 
the abdomen. The males (fig. 27) are quite different from 
the females (fig. 28), are much smaller, and have bell-shaped 
suckers upon the ends of their legs. The female is about one- 
sixtieth to one-seventieth of an inch in length (0.45mm. long 
and 0.35mm. wide), the male (0.283mm. by0.19mm., and the 
